newbrunswick, hi. Actually a very small percent of people with systemic lupus, something like 3% to 5%, remain ANA-negative. The autoantibody typically seen in this group is anti-Ro. The term "Ro-lupus" is sometimes used to describe such people. (I fell into this tiny group & had a very hard time getting answers.)

You also mention antiphospholipid syndrome. In the same vein, I *think* while it's most often seen with lupus, APS can sometimes occur without lupus.

When bloodwork isn't definitive but symptoms seem lupus-like, a skin specialist can do something called a lupus band test, which is a deep punch biopsy followed up by immunofluorescent stain tests on the skin samples. Those stain tests can light up in a way that's 100% unique to lupus, thus the LBT can be an extremely useful tool where blood results haven't provided answers. (I finally had an LBT done; it proved beyond all doubt that I have lupus.)

I had some of what you cite (rashes, hair loss, joint pain, fatigue, neuro-like tingling) but never a sense of "dead weight" in a limb. Have you also had consults with a neurologist, to determine if you've had clots or a stroke? An orthopedist (to check for spinal compression)?

In his lupus hardcover, Dr. Daniel Wallace discusses many tests; various subgroups of lupus; APS; how lupus is differentiated from other connective tissue diseases & from certain neurological conditions (MS, Parkinson's, etc.); symptoms by organ/body system; rashes; etc. Look in your local library. Other authors who cover the same ground are Dr. Robert Lahita and Dr. Graham Hughes.

You really do need to do some reading, I think. I hope you hit your library or bookstore tomorrow! Please let us know how you make out. All my best, Vee